Graphing an equation similar to a circle (or pair of Dependent Equations) for data

I am currently working on a project where I am taking a series of differential equations, solving for steady states, and then generating a model so that I can use that data to show some different graphs and then compare them. So from what I have done up until now I have this equation:

(x^2 + y^2) = (P*k*y)/w

and solved out for x and y it's:

x = +- sqrt((k*p*y)/w - y^2)

y = (k*p)/(2*w) +- sqrt([(k*p)/(2*w)]^2 - x^2)

I tried plugging it all into a simulink model but keep getting an algebraic loop that I can't figure out how to circumvent. I also thought of trying to modify the m-file for pplane8 found online at http://math.rice.edu/~dfield/ to export data to the workspace, but that might take a little more coding then I know at the moment.

Is there a way that I can graph this using an m-file or with a simulink model? I am still a 'beginner' with the software so I don't know the limitations really well. Thanks for the help in advance.

Answer 1

[bym]

You didn't give values for p, k & w , so I assumed they are all 1. So:

ezplot('x^2+y^2-y')
axis square

[Jon]

They are variables that I will be changing. At the moment I have

k=1.69

p=pi

w=2*pi